In the area of data processing, a field bus is any bus system that connects field devices in a vehicle or a facility such as sensors and actuators to a control or automation unit. Typical serial field buses such as the controller area network (CAN) common in vehicle technology define at least the bit transmission layer (physical layer) and securing layer (data link layer) in a reference model in accordance with ISO/IEC 7498-1:1994.
The content of a message is generally determined in this context by an object identification (object identifier, ID). For example, in a measuring system, a separate object identifier can be assigned to each of the parameters of temperature, voltage, and pressure. A list of the object identifiers, transmitters, receivers, and the most diverse metadata are typical components of a so-called communication matrix (C matrix). This is provided, for example by the respective original equipment manufacturer (OEM), under strict constraints in a project-specific manner or requires elaborate reverse engineering (RE).
EP 1 639 758 B1 discloses in exemplary fashion a method for exchanging data in messages between at least two subscribers, which are connected by a bus system, the messages containing the data being transmitted by the subscribers via the bus system and the messages being controlled temporally by a first subscriber in such a way that the first subscriber repeatedly transmits a reference message, which contains an item of time information of the first subscriber, in at least one specifiable time interval via the bus system, the time interval being subdivided as a base cycle into time windows of specifiable length and the messages being transmitted in the time windows, a communication matrix being used in the exchange of data, which comprises at least two base cycles, a pause time of modifiable duration being provided at the end of at least one base cycle in the communication matrix, by which a temporal deviation of the start of the base cycle is corrected by adapting the duration of the pause time within the communication matrix, and a correction value being ascertained for compensating the temporal deviation, which results from a local time of a subscriber and a cycle time and which is used as a measure of the correction for compensating the pause time.